Accommodative intraocular lens

ABSTRACT

A two-optic accommodative lens system. The first lens has a negative power and is located posteriorly against the posterior capsule. The periphery of the first optic contains a pair of clasps. The second optic is located anteriorly to the first optic and is of a positive power. The peripheral edge of the second optic contains a pair of locking arms that fit into the clasps contained on the periphery of the first optic to lock the second optic onto the first optic, but allow for rotation of the arms within the clasps. Hinge structures on the locking arms allow the second optic to move relative to the first optic along the optical axis of the lens system in reaction to movement of the ciliary muscle.

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to the field of intraocularlenses (IOL) and, more particularly, to accommodative IOLs.

[0002] The human eye in its simplest terms functions to provide visionby transmitting light through a clear outer portion called the cornea,and focusing the image by way of a crystalline lens onto a retina. Thequality of the focused image depends on many factors including the sizeand shape of the eye, and the transparency of the cornea and the lens.

[0003] When age or disease causes the lens to become less transparent,vision deteriorates because of the diminished light which can betransmitted to the retina. This deficiency in the lens of the eye ismedically known as a cataract. An accepted treatment for this conditionis surgical removal of the lens and replacement of the lens function byan artificial intraocular lens (IOL).

[0004] In the United States, the majority of cataractous lenses areremoved by a surgical technique called phacoemulsification. During thisprocedure, an opening is made in the anterior capsule and a thinphacoemulsification cutting tip is inserted into the diseased lens andvibrated ultrasonically. The vibrating cutting tip liquifies oremulsifies the lens so that the lens may be aspirated out of the eye.The diseased lens, once removed, is replaced by an artificial lens.

[0005] In the natural lens, bifocality of distance and near vision isprovided by a mechanism known as accommodation. The natural lens, earlyin life, is soft and contained within the capsular bag. The bag issuspended from the ciliary muscle by the zonules. Relaxation of theciliary muscle tightens the zonules, and stretches the capsular bag. Asa result, the natural lens tends to flatten. Tightening of the ciliarymuscle relaxes the tension on the zonules, allowing the capsular bag andthe natural lens to assume a more rounded shape. In the way, the naturallens can be focus alternatively on near and far objects.

[0006] As the lens ages, it becomes harder and is less able to changeshape in reaction to the tightening of the ciliary muscle. This makes itharder for the lens to focus on near objects, a medical condition knownas presbyopia. Presbyopia affects nearly all adults over the age of 45or 50.

[0007] Prior to the present invention, when a cataract or other diseaserequired the removal of the natural lens and replacement with anartificial IOL, the IOL was a monofocal lens, requiring that the patientuse a pair of spectacles or contact lenses for near vision. Allergan hasbeen selling an bifocal IOL, the Array lens, for several years, but dueto quality of issues, this lens has not been widely accepted.

[0008] Several designs for accommodative IOLs are being studied. Forexample, several designs manufactured by C&C Vision are currentlyundergoing clinical trials. See U.S. Pat. Nos. 6,197,059, 5,674,282,5,496,366 and 5,476,514 (Cumming), the entire contents of which beingincorporated herein by reference. The lens described in these patents isa single optic lens having flexible haptics that allows the optic tomove forward and backward in reaction to movement of the ciliary muscle.A similar designs are described in U.S. Pat. No. 6,302,911 B1 (Hanna),Pat. Nos. 6,261,321 B1 and 6,241,777 B1 (both to Kellan), the entirecontents of which being incorporated herein by reference. The amount ofmovement of the optic in these single-lens systems, however, may beinsufficient to allow for a useful range of accommodation. In addition,as described in U.S. Pat. Nos. 6,197,059, 5,674,282, 5,496,366 and5,476,514, the eye must be paralyzed for one to two weeks in order forcapsular fibrosis to entrap the lens that thereby provide for a rigidassociation between the lens and the capsular bag. In addition, thecommercial models of these lenses are made from a hydrogel or siliconematerial. Such materials are not inherently resistive to the formationof posterior capsule opacification (“PCO”). The only treatment for PCOis a capsulotomy using a Nd:YAG laser that vaporizes a portion of theposterior capsule. Such destruction of the posterior capsule may destroythe mechanism of accommodation of these lenses.

[0009] There have been some attempts to make a two-optic accommodativelens system. For example, U.S. Pat. No. 5,275,623 (Sarfarazi), WIPOPublication No. 00/66037 (Glick, et al.) and WO 01/34067 A1 (Bandhauer,et al), the entire contents of which being incorporated herein byreference, all disclose a two-optic lens system with one optic having apositive power and the other optic having a negative power. The opticsare connected by a hinge mechanism that reacts to movement of theciliary muscle to move the optics closer together or further apart,thereby providing accommodation. In order to provide this “zoom lens”effect, movement of the ciliary muscle must be adequately transmitted tothe lens system through the capsular bag, and none of these referencesdisclose a mechanism for ensuring that there is a tight connectionbetween the capsular bag and the lens system. In addition, none of theselenses designs have addressed the problem with PCO noted above.

[0010] Therefore, a need continues to exist for a safe and stableaccommodative intraocular lens system that provides accommodation over abroad and useful range.

BRIEF SUMMARY OF THE INVENTION

[0011] The present invention improves upon the prior art by providing atwo-optic accommodative lens system. The first lens has a negative powerand is located posteriorly against the posterior capsule. The peripheryof the first optic contains a pair of clasps. The second optic islocated anteriorly to the first optic and is of a positive power. Theperipheral edge of the second optic contains a pair of locking arms thatfit into the clasps contained on the periphery of the first optic tolock the second optic onto the first optic, but allow for rotation ofthe arms within the clasps. Hinge structures on the locking arms allowthe second optic to move relative to the first optic along the opticalaxis of the lens system in reaction to movement of the ciliary muscle.

[0012] Accordingly, one objective of the present invention is to providea safe and biocompatible intraocular lens.

[0013] Another objective of the present invention is to provide a safeand biocompatible intraocular lens that is easily implanted in theposterior chamber.

[0014] Still another objective of the present invention is to provide asafe and biocompatible intraocular lens that is stable in the posteriorchamber.

[0015] Still another objective of the present invention is to provide asafe and biocompatible accommodative lens system.

[0016] These and other advantages and objectives of the presentinvention will become apparent from the detailed description and claimsthat follow.

BRIEF DESCRIPTION OF THE DRAWING

[0017]FIG. 1 is an enlarged top plan view of the first optic of a firstembodiment of the lens system of the present invention.

[0018]FIG. 2 is an enlarged cross-sectional view of the first optic of afirst embodiment of the lens system of the present invention taken atline 2-2 in FIG. 1.

[0019]FIG. 3 is an enlarged top plan view of the second optic of a firstembodiment of the lens system of the present invention.

[0020]FIG. 4 is an enlarged cross-sectional view of the second optic ofa first embodiment of the lens system of the present invention taken atline 4-4 in FIG. 3.

[0021]FIG. 5 is an enlarged partial cross-sectional view taken at circle5 in FIG. 4.

[0022]FIG. 6 is an enlarged top plan view of the first optic of a secondembodiment of the lens system of the present invention.

[0023]FIG. 7 is an enlarged cross-sectional view of the first optic of asecond embodiment of the lens system of the present invention taken atline 7-7 in FIG. 6.

[0024]FIG. 8 is an enlarged top plan view of the second optic of asecond embodiment of the lens system of the present invention.

[0025]FIG. 9 is an enlarged cross-sectional view of the second optic ofa second embodiment of the lens system of the present invention taken atline 9-9 in FIG. 8.

[0026]FIG. 10 is a cross-sectional view of the first embodiment of thelens system of the present invention illustrated in FIGS. 1-5.

[0027]FIG. 11 is a cross-sectional view of the second embodiment of thelens system of the present invention illustrated in FIGS. 6-9.

[0028]FIG. 12 is a cross-sectional view of the first embodiment of thelens system of the present invention illustrated in FIGS. 1-5 andillustrating the lens system implanted within a capsular bag.

[0029]FIG. 13 is a cross-sectional view of the second embodiment of thelens system of the present invention illustrated in FIGS. 6-9 andillustrating the lens system implanted within a capsular bag.

[0030]FIG. 14 is an enlarged top plan view of the first optic of a thirdembodiment of the lens system of the present invention.

[0031]FIG. 15 is an enlarged cross-sectional view of the first optic ofa third embodiment of the lens system of the present invention taken atline 15-15 in FIG. 14.

[0032]FIG. 16 is an enlarged partial cross-sectional view taken atcircle 16 in FIG. 15.

[0033]FIG. 17 is an enlarged top plan view of the second optic of athird embodiment of the lens system of the present invention.

[0034]FIG. 18 is an enlarged cross-sectional view of the second optic ofa third embodiment of the lens system of the present invention taken atline 18-18 in FIG. 17.

[0035]FIG. 19 is an enlarged partial cross-sectional view taken atcircle 19 in FIG. 18.

[0036]FIG. 20 is an enlarged top plan view of the third embodiment ofthe lens system of the present invention illustrated in FIGS. 14-19.

[0037]FIG. 21 is a cross-sectional view of the third embodiment of thelens system of the present invention taken at line 21-21 in FIG. 20.

[0038]FIG. 22 is an enlarged top plan view of the first optic of afourth embodiment of the lens system of the present invention.

[0039]FIG. 23 is an enlarged cross-sectional view of the first optic ofa third embodiment of the lens system of the present invention taken atline 23-23 in FIG. 22.

[0040]FIG. 24 is an enlarged top plan view of the second optic of afourth embodiment of the lens system of the present invention.

[0041]FIG. 25 is an enlarged cross-sectional view of the second optic ofa third embodiment of the lens system of the present invention taken atline 25-25 in FIG. 24.

[0042]FIG. 26 is an enlarged partial cross-sectional view taken atcircle 26 in FIG. 25.

[0043]FIG. 27 is an enlarged top plan view of the fourth embodiment ofthe lens system of the present invention illustrated in FIGS. 26-26.

[0044]FIG. 28 is a cross-sectional view of the fourth embodiment of thelens system of the present invention taken at line 28-28 in FIG. 27.

DETAILED DESCRIPTION OF THE INVENTION

[0045] As best seen in FIGS. 1-5 and 10, lens system 10 of the presentinvention generally consists of posterior optic 12 and anterior optic14. Optic 12 is preferably formed in any suitable overall diameter orlength, for example, around 12 millimeters, for implantation in theposterior chamber. Optic 12 preferably is made from a soft, foldablematerial that is inherently resistive to the formation of PCO, such as asoft acrylic. Optic 14 preferable is made from a soft, foldable materialsuch as a hydrogel, silicone or soft acrylic. Optic 12 may be anysuitable power, but preferably has a negative power. Optic 14 may alsobe any suitable power but preferably has a positive power. The relativepowers of optics 12 and 14 should be such that the axial movement ofoptic 14 toward or away from optic 12 should be sufficient to adjust theoverall power of lens system 10 at least one diopter and preferably, atleast three to four diopters, calculation of such powers of optics 12and 14 being within the capabilities of one skilled in the art ofdesigning ophthalmic lenses by, for example, using the followingequations:

P=P ₁ +P ₂ −T/n*P ₁ P ₂  (1)

δP=δT/n*P ₁P₂  (2)

[0046] As best seen in FIGS. 1 and 2, optic 12 is generally symmetricalabout optical axis 22 and contains a pair of opposing clasps 16 that areshaped to stretch and fill equatorial region 210 of capsular bag 200.Clasps 16 contain sockets 18 generally defined by latch 20. As best seenin FIGS. 3-5, optic 14 contains a pair of haptics 24 that are connectedto optic 14 by hinge regions 26 and contain locking pins 28 distallyfrom hinge regions 26. As seen in FIG. 10, locking pins 28 are sized andshaped to fit within sockets 18 on optic 12, thereby holding optic 14firmly within optic 12 while still permitting rotation of locking pins28 within sockets 18. One skilled in the art will recognize that sockets18 may be located on hinge regions 26 and that locking pins 28 may belocated on optic 12. In order to insert locking pins 28 within sockets18, sockets 18 may be spread apart slightly, thereby preloading haptics24. Once implanted in an eye, as one skilled in the art will recognize,contraction of capsular bag 200 will cause clasps 16 to collapseslightly, thereby causing compression of optic 14. As optic 14 iscompressed, hinge regions 26 allow optic 14 to vault anteriorly awayfrom optic 12, with locking pins 28 pivoting within sockets 18. Oneskilled in the art will recognize that no specific feature needs to beused to form hinge regions 26 as haptics 24 may be formed from amaterial and/or in such a configuration that haptics naturally flex inthe manner of a hinge.

[0047] As best seen in FIGS. 6-9 and 11, lens system 110 of the presentinvention generally consisting of posterior optic 112 and anterior optic114. Optic 112 is preferably formed in any suitable overall diameter orlength, for example, around 12 millimeters, for implantation in theposterior chamber. Optic 112 preferably is made from a soft, foldablematerial that is inherently resistive to the formation of PCO, such as asoft acrylic. Optic 114 preferable is made from a soft, foldablematerial such as a hydrogel, silicone or soft acrylic. Optic 112 may beany suitable power, but preferably has a negative power. Optic 114 mayalso be any suitable power but preferably has a positive power. Therelative powers of optics 112 and 114 should be such that the axialmovement of optic 114 toward or away from optic 112 should be sufficientto adjust the overall power of lens system 10 at least one diopter andpreferably, at least three to four diopters, calculation of such powersof optics 112 and 114 being within the capabilities of one skilled inthe art. One skilled in the art will also recognize that the axialmovement of optic 114 relative to optic 112 is greater in thisembodiment as opposed to the embodiment illustrated in FIGS. 1-5 due tothe longer length of haptic 124 versus haptic 24.

[0048] As best seen in FIGS. 6, 7 and 13, optic 112 is generallysymmetrical about optical axis 122 and contains a pair of opposingclasps 116 that are shaped to stretch and fill equatorial region 310 ofcapsular bag 300. Clasps 116 contain sockets 118 generally defined bylatch 120. As best seen in FIGS. 8 and 9, optic 114 containscircumferential haptic 124 that are connected to optic 114 by hingeregions 126 and contain locking pins 128 distally on the periphery ofhaptics 124. One skilled in the art will recognize that sockets 118 maybe located on clasps 116 and that locking pins 128 may be located onhaptics 124. As seen in FIG. 11, locking pins 128 are sized and shapedto fit within sockets 118 on optic 112, thereby holding optic 114 firmlywithin optic 112 while still permitting rotation of locking pins 128within sockets 118. Preferably, locking pins 128 are locatedapproximately 90° from hinge regions 126 around the circumference ofoptic 114. In order to insert locking pins 128 within sockets 118,sockets 118 may be spread apart slightly, thereby preloading haptics124. One skilled in the art will recognize that no specific featureneeds to be used to form hinge regions 126 as haptics 124 may be formedfrom a material and/or in such a configuration that haptics naturallyflex in the manner of a hinge.

[0049] Once implanted in an eye, as one skilled in the art willrecognize, contraction of capsular bag 300 will cause clasps 116 tocollapse slightly, thereby causing compression of optic 114. As optic114 is compressed, hinge regions 126 allow optic 114 to vault anteriorlyaway from optic 112, with locking pins 128 pivoting within sockets 118.

[0050] As best seen in FIGS. 12 and 13, lens system 10 and 110 fillscapsular bag 200 and 300, respectively, following removal of the naturallens. In order to remove the natural lens, an opening or rhexis isnormally made in the anterior side of capsule 200 or 300. The openingcontains rim or margin 212 or 312 During implantation of system 10 or110, rim or margin 212 or 312 is inserted into socket 18 or 118 prior tothe introduction of optic 14 or 114, respectively. Once optic 14 or 114is installed in optic 12 or 112, locking pins 28 and 128 help to containrim 212 or 312 within sockets 18 or 118, respectively, therebymaintaining a positive mechanical connection between capsular bag 200and 300 and lens system 10 and 110, respectively. Contraction ofcapsular bag 200 or 300 will therefore be more directly translated intocontraction of optics 12 and 112, respectively. In addition, theself-locking design of sockets 18 and 118 prevent capsular bag 200 and300 from slipping out of sockets 18 or 118, respectively.

[0051] As best seen in FIGS. 15-21, lens system 410 of the presentinvention of the present invention generally consists of posterior optic412 and anterior optic 414. Optic 412 is preferably formed in anysuitable overall diameter or length, for example, around 12 millimeters,for implantation in the posterior chamber. Optic 412 preferably is madefrom a soft, foldable material that is inherently resistive to theformation of PCO, such as a soft acrylic. Optic 414 preferable is madefrom a soft, foldable material such as a hydrogel, silicone or softacrylic. Optic 412 may be any suitable power, but preferably has anegative power. Optic 414 may also be any suitable power but preferablyhas a positive power. The relative powers of optics 412 and 414 shouldbe such that the axial movement of optic 414 toward or away from optic412 should be sufficient to adjust the overall power of lens system 410at least one diopter and preferably, at least three to four diopters,calculation of such powers of optics 412 and 414 being within thecapabilities of one skilled in the art as described above.

[0052] As best seen in FIGS. 15 and 16, optic 412 is generallysymmetrical about optical axis 422 and contains a circumferential socket418. As best seen in FIGS. 17-19, optic 414 contains a pair ofhemispherical haptics 424 that are connected to optic 414 by hingeregions 426 and contain circumferential locking rib 428. As seen in FIG.21, locking rib 428 is sized and shaped to fit within socket 418 onoptic 412, thereby holding optic 414 firmly within optic 412 whileallowing rotation of locking rib 428 within socket 418. Once implantedin an eye, as one skilled in the art will recognize, contraction of thecapsular bag will cause compression of optic 414. As optic 414 iscompressed, hinge regions 426 allow optic 414 to vault anteriorly awayfrom optic 412, with locking rib 428 pivoting within socket 418.

[0053] As best seen in FIGS. 22-28, lens system 510 of the presentinvention of the present invention is similar to system 510 andgenerally consists of posterior optic 512 and anterior optic 514. Optic512 is preferably formed in any suitable overall diameter or length, forexample, around 12 millimeters, for implantation in the posteriorchamber. Optic 512 preferably is made from a soft, foldable materialthat is inherently resistive to the formation of PCO, such as a softacrylic. Optic 514 preferable is made from a soft, foldable materialsuch as a hydrogel, silicone or soft acrylic. Optic 512 may be anysuitable power, but preferably has a negative power. Optic 514 may alsobe any suitable power but preferably has a positive power. The relativepowers of optics 512 and 514 should be such that the axial movement ofoptic 514 toward or away from optic 512 should be sufficient to adjustthe overall power of lens system 510 at least one diopter andpreferably, at least three to four diopters, calculation of such powersof optics 512 and 514 being within the capabilities of one skilled inthe art as described above.

[0054] As best seen in FIGS. 22 and 23, optic 512 is generallysymmetrical about optical axis 522 and contains a circumferential rib528, which is similar to rib 428 in system 410. As best seen in FIGS.24-26, optic 514 contains a pair of hemispherical haptics 524 that areconnected to optic 514 by hinge regions 526 and contain circumferentialsocket 518. As seen in FIG. 28, locking rib 528 is sized and shaped tofit within socket 518 on optic 514, thereby holding optic 514 firmlywithin optic 512 while allowing rotation of locking rib 528 withinsocket 518. Once implanted in an eye, as one skilled in the art willrecognize, contraction of the capsular bag will cause compression ofoptic 514. As optic 514 is compressed, hinge regions 526 allow optic 514to vault anteriorly away from optic 512, with locking rib 528 pivotingwithin socket 518.

[0055] This description is given for purposes of illustration andexplanation. It will be apparent to those skilled in the relevant artthat changes and modifications may be made to the invention describedabove without departing from its scope or spirit.

We claim:
 1. An intraocular lens, comprising: a) a first optic having aclasp with a socket; b) a second optic having at least one haptic, thehaptic being connected to the second optic by a hinge region; and c) alocking pin located on the haptic, the locking pin sized and shaped tobe received in the socket and thereby movably attach the second optic tothe first optic.
 2. The lens of claim 1 wherein the hinge region allowsthe second optic to vault away from the first optic in reaction tocompression of the first optic.
 3. The lens of claim 1 wherein the firstoptic and the second optic comprise a soft acrylic.
 4. The lens of claim1 wherein the second optic comprises a hydrogel.
 5. The lens of claim 1wherein the second optic comprises silicone.
 6. The lens of claim 1wherein the locking pin and socket are sized and shaped to retain ananterior capsular rhexis rim when the locking pin is installed withinthe socket.
 7. The lens of claim 1 wherein the second optic has acircumference and the locking pin is located approximately 90° aroundthe circumference from the hinge region.
 8. A method of retaining a lensin a capsular bag, comprising the steps of: a) providing a first optichaving a clasp with a socket; b) providing a second optic having atleast one haptic, the haptic being connected to the second optic by ahinge region the haptic containing a locking pin, the locking pin sizedand shaped to be received in the socket; c) providing an opening in ananterior capsular bag, the opening having a rim; d) placing the rim ofthe anterior capsule opening in the socket; and e) inserting the lockingpin into the socket so as to retain the rim in the socket and movablyattach the second optic to the first optic.
 9. The lens of claim 8wherein the hinge region allows the second optic to vault away from thefirst optic in reaction to compression of the first optic.
 10. The lensof claim 8 wherein the first optic and the second optic comprise a softacrylic.
 11. The lens of claim 8 wherein the second optic comprises ahydrogel.
 12. The lens of claim 8 wherein the second optic comprisessilicone.
 13. The lens of claim 8 wherein the locking pin and socket aresized and shaped to retain an anterior capsular rhexis rim when thelocking pin is installed within the socket.
 14. An intraocular lens,comprising: a) a first optic having a clasp with a socket; b) a secondoptic having at least one haptic, the haptic being hingedly connected tothe second optic; and c) a locking pin located on the haptic, thelocking pin sized and shaped to be received in the socket and therebymovably attach the second optic to the first optic.
 15. The lens ofclaim 14 wherein the haptic allows the second optic to vault away fromthe first optic in reaction to compression of the first optic.
 16. Thelens of claim 14 wherein the first optic and the second optic comprise asoft acrylic.
 17. The lens of claim 14 wherein the second opticcomprises a hydrogel.
 18. The lens of claim 14 wherein the second opticcomprises silicone.
 19. The lens of claim 14 wherein the locking pin andsocket are sized and shaped to retain an anterior capsular rhexis rimwhen the locking pin is installed within the socket.
 20. A method ofretaining a lens in a capsular bag, comprising the steps of: a)providing a first optic having a clasp with a socket; b) providing asecond optic having at least one haptic, the haptic being hingedlyconnected to the second optic, the haptic containing a locking pin, thelocking pin sized and shaped to be received in the socket; c) providingan opening in an anterior capsular bag, the opening having a rim; d)placing the rim of the anterior capsule opening in the socket; and e)inserting the locking pin into the socket so as to retain the rim in thesocket and movably attach the second optic to the first optic.
 21. Thelens of claim 20 wherein the haptic allows the second optic to vaultaway from the first optic in reaction to compression of the first optic.22. The lens of claim 20 wherein the first optic and the second opticcomprise a soft acrylic.
 23. The lens of claim 20 wherein the secondoptic comprises a hydrogel.
 24. The lens of claim 20 wherein the secondoptic comprises silicone.
 25. The lens of claim 20 wherein the lockingpin and socket are sized and shaped to retain an anterior capsularrhexis rim when the locking pin is installed within the socket.
 26. Anintraocular lens, comprising: a) a first optic having a circumferentialsocket; b) a second optic having at least one haptic, the haptic beingconnected to the second optic by a hinge region; and c) acircumferential locking rib located on the haptic, the locking rib sizedand shaped to be received in the socket and thereby movably attach thesecond optic to the first optic.
 27. The lens of claim 26 wherein thehinge region allows the second optic to vault away from the first opticin reaction to compression of the first optic.
 28. The lens of claim 26wherein the first optic and the second optic comprise a soft acrylic.29. The lens of claim 26 wherein the second optic comprises a hydrogel.30. The lens of claim 26 wherein the second optic comprises silicone.31. The lens of claim 26 wherein the locking rib and socket are sizedand shaped to retain an anterior capsular rhexis rim when the lockingrib is installed within the socket.
 32. An intraocular lens, comprising:a) a first optic having a circumferential locking rib; b) a second optichaving at least one haptic, the haptic being connected to the secondoptic by a hinge region; and c) a circumferential socket located on thehaptic, the socket sized and shaped to receive the locking rib andthereby movably attach the second optic to the first optic.
 33. The lensof claim 32 wherein the hinge region allows the second optic to vaultaway from the first optic in reaction to compression of the first optic.34. The lens of claim 32 wherein the first optic and the second opticcomprise a soft acrylic.
 35. The lens of claim 32 wherein the secondoptic comprises a hydrogel.
 36. The lens of claim 32 wherein the secondoptic comprises silicone.
 37. The lens of claim 32 wherein the lockingrib and socket are sized and shaped to retain an anterior capsularrhexis rim when the locking rib is installed within the socket.